The The Drug Interactions component at Drugs.com simply suggests a titration method to start Wellbutrin.

Yes, some of the older antidepressants do work better with/for PD. I take nortriptyline and it has made a difference for me.

See: Tricyclic antidepressants best for depression in Parkinson's
17. December 2008 19:48
http://www.news-medical.net/news/2008/12/17/44349.aspx
Excerpt: In the study, scientists gave 52 people diagnosed with Parkinson's disease and depression either nortriptyline, a tricyclic antidepressant (TCA), paroxetine CR, a selective serotonin reuptake inhibitor (SSRI) or a placebo pill. Tricyclics affect both norepinephrine and serotonin, two different receptors in the brain. The people were tested for improvement of depression symptoms at two, four and eight weeks after starting treatment.

Drug.com: Interactions between your selected drugs:

Wellbutrin (buPROPion) and levodopa (Ingredient of Sinemet) (Moderate Drug-Drug)

ADJUST DOSE: According to the product labeling for bupropion [Wellbutrin], limited clinical data suggest a higher incidence of adverse experiences in patients receiving bupropion concurrently with either levodopa or amantadine. Neither the mechanism of interaction nor specific adverse effects are cited. According to a published case report, neurotoxic effects including ataxia, dizziness, vertigo, agitation, tremors, and gait abnormalities occurred in 3 elderly patients following addition of amantadine to bupropion therapy. The symptoms resolved within 72 hours after discontinuation of both drugs. The authors theorize that additive central dopaminergic effects of the drugs may have caused the apparent interaction.

MANAGEMENT: Caution is advised if bupropion is used with levodopa or amantadine. The manufacturer recommends a lower initial dosage of bupropion and gradual dosage increments in patients receiving the drugs concurrently.

Side Effects of nortriptyline:

"In fact, most people tolerate the medication well. When people do develop nortriptyline side effects, in many cases they are minor, meaning they require no treatment or are easily treated by you or your healthcare provider."

Interactions between Sinemet and nortriptyline, per Drugs.com: "Anecdotal reports also suggest that coadministration of tricyclic antidepressants and levodopa or carbidopa may occasionally result in hypertensive episodes; however, causality was not clearly established. The mechanism is unknown. Until more information is available, it may be prudent to monitor patients for altered efficacy and safety."